Socket contacts of a socket connected with terminals of a power line or the like for transmitting high-voltage high-current power may be hot connected to the plug pins of a plug to supply power to electric equipment connected with the plug. In the instant when the plug pins are connected to or disconnected from the socket contacts, high electric energy is accumulated and an arc discharge occurs between the adjoining members. Such an arc discharge can also be caused by induced electromotive force that occurs when plug pins connected with an inductive load are pulled off from the socket contacts of a socket connected with a power line.
An arc discharge can erode the plug pins of the plug and the socket contacts and accelerate degradation. Various methods have conventionally been proposed to suppress the occurrence of an arc discharge or reduce the effect thereof. For example, Patent Literature 1 discloses a method in which permanent magnets are arranged in a direction orthogonal to an opposed direction of a pair of contacts to apply a magnetic field. With this configuration, an arc is deflected by the Lorentz force to prevent damage from an arc discharge to the contacts.